After planetfall, Uhura informs CaptainKirk that she is in contact with an Iotian named Bela Okmyx who describes himself as "Boss". Okmyx invites Kirk to come down to the planet's surface saying that a "reception committee" will be waiting for him upon arrival. Since the Horizon's visit was before the Federation's Prime Directive against non-interference, Kirk, Spock and McCoy are concerned about what effects the Horizon's crew may have had on the Iotian culture which was just beginning industrialization at the time and have a knack for imitation. The three beam down to find a culture resembling that of Chicago in the 1920s. They are immediately greeted by two men dressed as gangsters who threaten them with Tommy guns.

The landing party surrenders its standard phasers and communicators and are asking questions of the gunmen when a drive-by shooting occurs. One of the gunmen is killed; the other refers to the "hit" being committed by someone named Krako. Kirk, Spock and McCoy are taken to Okmyx's office, where they learn that Okmyx is one of a dozen or so "Bosses" and that he has the largest territory on Iotia. The office contains a book (referred to as "The Book") published in the year 1992 titled Chicago Mobs of the Twenties. Okmyx informs Kirk, Spock, and McCoy that "The Book" was left by the crew of the Horizon, and the landing party correctly deduces that the entire Iotian culture has been formed by "This Book". Okmyx refers to the landing party as "Feds" and tells them he wants the Enterprise to furnish him with "heaters" so he can wipe out all of the other Bosses and take total control of the planet. Kirk refuses and Okmyx gives him just eight hours to provide the weapons or die.

Okmyx has the landing party taken to a warehouse under guard. He then takes one of the confiscated communicators and contacts the Enterprise. He threatens to kill the landing party unless the ship provides him with one hundred phasers (which he calls "heaters") and troops to show him how to use them.

An angry Jojo Krako

In the warehouse the gunmen are playing cards on a makeshift table while the landing party speculates while sitting in the background about the future of the Iotian society. Spock reasons that, although Okmyx's methods may seem deplorable, his ultimate goal is what the Enterprise crew must also work for: Iotia's society must become united or it will break down completely into anarchy. Kirk feels that since a Federation vessel contaminated the culture, it's the Enterprise's responsibility to set things right from this mess the planet's inhabitants are currently in. He distracts one of the gunmen named Kalo with a nonsensical and nonexistent card game supposedly from Beta Antares IV called "Fizzbin" which he makes up on the spot, enabling the landing party to overpower the gunmen and escape. Kirk grabs one of the mobster's Tommy gun and instructs Spock and McCoy to find the local radio station, contact the ship, and have themselves beamed aboard.

Kirk goes off by himself planning on abducting Okmyx and bringing him back to the Enterprise. He is promptly greeted by a new gunman, named Zabo, and is forced to take a ride. Kirk is taken to the office of Jojo Krako, another boss who wants to be in control of the planet. Kirk again refuses to "come across with the heaters" for Krako and is confined to a small room.

Spock uses AM radio to talk to Uhura

Spock and McCoy find the radio station. Spock incapacitated the station's operator with a Vulcan nerve pinch and they manage to contact Lieutenant Uhura and return to the ship. Shortly after, Okmyx contacts the ship through the communicator he stole and informs Spock that Krako has kidnapped Kirk. He offers to assist in getting Kirk back if Spock and McCoy will return to his office. Spock finds it difficult to trust Okmyx but decides to rather than use blatant force.

Using wire from a radio, Kirk rigs a trip line across the doorway and then yells out for help. He knocks out two gunmen and escapes with a machine gun.

In the transporter room, Spock instructs Scott to set one of the ship's phaser banks to a strong stun setting. He and McCoy then beam down to Okmyx's office where they are again met by armed hoods.

"Ship's log, Mr. Spock reporting. Incredible as it seems, Dr. McCoy and I are once again prisoners of the chief criminal boss of a society patterned after old Earth gangsters."

Okmyx again takes them prisoner, but Kirk arrives and turns the tables. Kirk and Spock dress in the clothes of Kalo and one of Okmyx's henchmen, commandeer a car and set out to "put the bag" on Krako. They are assisted by a small boy who demands "a piece of the action" in exchange for creating a diversion. The boy poses as Kirk's son and pretends to be injured, so Kirk and Spock can incapacitate the guards. They break into Krako's headquarters and appear to be in control until Krako's men gain the upper hand.

Kirk tells Krako that the Federation is taking over and arranges, via an indirect order to Scotty, to have Krako beamed up to the Enterprise to show him what he's up against. They overpower Krako's men in the process and then head back to Okmyx's office where Kirk has Scott locate and transport the other Bosses including Krako. Tepo is successfully transported, though, before more are located, an argument arises and Tepo casts doubt and supposes there aren't more people than just the three "Feds" he sees.

Soon, on the street below, Krako's men try a hit on Okmyx's territory in an attempt to rescue Krako and a gunfight ensues in the street below. The landing party loses their guns once again, and Kirk has the ship fire its phasers on wide stun in the surrounding area to demonstrate their power. The mobsters are now convinced and agree to Federation control with Okmyx as the top boss and Krako as his lieutenant. They call the new structure a syndicate.

Back aboard ship, Spock has concerns about Kirk's solution of having the Federation take a 40% cut of the planet's annual "action". Kirk explains that the money will go back into the planetary treasury to help the Federation guide the Iotians into a more ethical society. Spock has his doubts as to the logic behind Kirk's plan.

McCoy is concerned because he seems to have left his communicator behind somewhere in Okmyx's office. Kirk and Spock speculate that with that kind of technology, such as the communicator's transtator in the hands of the Iotians and with their gift for imitation, the Iotians may one day want a piece of the Federation's action.

"Okay, you three, let's see you petrify."
"Sir, would you mind explaining that statement, please?"
"I want to see you turn to stone. Put your hands over your head, or you ain't going to have no head to put your hands over."

- Kalo and Spock, as Kirk, Spock and McCoy arrive on Sigma Iotia II

"I got the biggest in the world. You know, there's one thing wrong with having the biggest. There's always some punk trying to cut you out."

- Okmyx, explaining to Kirk that he runs the biggest territory on Sigma Iotia II

"I’m gonna give you just eight hours to get me the things I want. If I don’t have those tools by then, I’m gonna call up your ship and have them pick you up…in a box!"

Gene Roddenberry jotted down the idea for this episode – a one-sentence synopsis titled "President Capone" – on the very first page of his very first Star Trek series proposal in 1964.

Early in the first season, George Clayton Johnson wrote an outline based on this premise, called "The Syndicate". Roddenberry liked it, and hired Johnson to develop it further. Johnson wrote a treatment entitled "Chicago II". However, as he got occupied with developing and writing "The Man Trap", this concept was forgotten. During the second season, then-producer Gene L. Coon discovered the treatment, and decided to use it, as he felt that, after the success of "The Trouble with Tribbles", the series needed more comedy-themed episodes. [1]

David P. Harmon and Coon's first draft script, entitled "Mission into Chaos" featured the Romulans trying to exploit the borderline planet Dana Iotia II, which the Federation wants to industrialize. Much to the crew's surprise, the planet is ruled by gangster bosses, based on the book Chicago Mobs of the Twenties. Kirk has to negotiate with Bela Okmyx and the other crime bosses, outsmarting the two Romulan agents, Rorek and Ramo, who try to lure Bela with sending him weapons and troops. At the end, the Iotians agreed to make a treaty, and send an ambassador to the Federation. But since every boss had a vote, they all "naturally" voted for themselves, and hence, they are all beamed aboard the Enterprise to be escorted to the diplomatic talks. [2]

No stardate is actually logged in the episode. A stardate of 4598.0 appeared in Bjo Trimble's Star Trek Concordance, apparently using an earlier script version, and the fotonovel provides a closing stardate 4598.7.

The scene when Kirk puts his feet up on Krako's table and declares that now the Federation is "taking over the whole ball of wax" is reminiscent of a similar scene in Mervyn LeRoy's classic gangster film, Little Caesar.

The plot for the Star Trek: 25th Anniversary Nintendo game has the Enterprise thrown outside of known space entering the Sigma Iotia system. When they finally get back, they find that McCoy leaving his communicator behind was responsible for the incident and they go back in time to retrieve it from the gangsters.

In Shane Johnson's reference book The Worlds of the Federation, in the entry on Iotia, the planet is referred to as being known indigenously as "Okmyx." Johnson also explains that the Iotians's discovery of McCoy's communicator led them to abandon their mobster culture and seize on the opportunity it presented; he adds that the next ship to orbit the planet (which he does not identify) found what, at first, appeared to be a Federation starbase, complete with uniformed personnel and communications on Star Fleet channels. He concludes, drawing this detail from the "Star System Data" booklet that accompanied the first Star Trek Maps, that Sigma Iotia II was subsequently declared a Federation Protectorate, with a cultural rating of E+ on the "Richter Scale of Cultures," and that though no quarantine was imposed, an orbital customs facility was eventually constructed, through which visiting personnel had to be cleared before they were permitted to beam to the surface.

The events of the episode are recapped in the comic "... Let's Kill All the Lawyers! when Bela Okmyx was one of the witnesses at James T. Kirk's trial. Okmyx revealed at Kirk's trial that the captain's cut of Iotia's "action" was still being skimmed for him. Okmyx also returned Leonard McCoy's communicator (which the doctor had left behind on Iotia), saying that the Iotians didn't do anything with the device and just put it away for safekeeping.

The landing party wears their number-one type phasers on their right hips, hanging vertically from their belts, emitter tubes downward. This placement is unique to this episode.

The street seen throughout this episode is on the Paramount lot and can be seen in many television series. The steps leading up to Okmyx' headquarters were used in the Judd Hirsch series Dear John.

The car that Kirk drove to "put the bag on Krako" had a V-12 engine, as a V-12 emblem is seen on the radiator. It was a Cadillac, probably a 1931 model. [3] Note the winged radiator cap, which Cadillacs of that vintage had. It is a nod to Chicago crime boss, Al "Scarface" Capone, who had a 1928 V-12 Cadillac. Incidentally, this represents the only time that a member of the crew ever operated any kind of land vehicle during the course of the original series.

Bantam Books published a series of novelizations called Star Trek Fotonovels which took photographic stills from actual episodes and arranged word balloons and text over them, to create a comic book formatted story. The eighth installment was an adaptation of this episode which contained a foreword written by Anthony Caruso in the character of Bela Okmyx. He mentions that he was elected president of the planet in a landslide and that he made Jojo Krako his vice president. The arrangement worked out well, he said, as he hadn't heard from Krako since.

According to the production report for the Star Trek: Enterprise episode "The Communicator", that episode explored a premise hinted at in this episode when Dr. McCoy confessed to leaving behind his communicator on Sigma Iotia II. "The Communicator" picked up on this idea, with a far more serious tone, after Lt. Reed loses his communicator on a pre-warp planet, but he and Archer go back to retrieve it, but things do not go well. [4](X)

The remastered version of "A Piece of the Action" aired in many North American markets during the weekend of 28 April2007. While the episode required very few new effects, the planet Sigma Iotia II was given a CGI-makeover, now a more Earth-like planet. Aside from orbital establishing shots, new phaser effects were created depicting the block-wide stun implemented from the Enterprise, replacing the more "cartoonish" aspects of the original.